/// <summary>
/// Determines whether the captcha is valid, and write error message if need.
/// </summary>
/// <param name="controller">
/// The specified <see cref="ControllerBase" />.
/// </param>
/// <param name="parameterContainer">
/// The specified <see cref="IParameterContainer" />.
/// </param>
/// <returns>
/// <c>True</c> if the captcha is valid; otherwise, <c>false</c>.
/// </returns>
public virtual bool ValidateCaptcha(ControllerBase controller, IParameterContainer parameterContainer)
{
Validate.ArgumentNotNull(controller, "controller");
Validate.ArgumentNotNull(parameterContainer, "parameterContainer");
if (IntelligencePolicy != null)
{
var isValid = IntelligencePolicy.IsValid(this, controller, parameterContainer);
if (isValid.HasValue)
{
if (isValid.Value)
{
return(true);
}
WriteError(controller, parameterContainer);
return(false);
}
}
ValueProviderResult tokenValue = controller.ValueProvider.GetValue(TokenElementName);
ValueProviderResult inputText = controller.ValueProvider.GetValue(InputElementName);
if (tokenValue != null && !string.IsNullOrEmpty(tokenValue.AttemptedValue) && inputText != null)
{
ICaptchaValue captchaValue = StorageProvider.GetValue(tokenValue.AttemptedValue, TokenType.Validation);
if (captchaValue != null && !string.IsNullOrEmpty(inputText.AttemptedValue) &&
captchaValue.IsEqual(inputText.AttemptedValue))
{
return(true);
}
}
WriteError(controller, parameterContainer);
return(false);
}
/// <summary>
/// Creates a new <see cref="IBuildInfoModel" /> for update a captcha.
/// </summary>
/// <param name="parameterContainer">
/// The specified <see cref="IParameterContainer" />.
/// </param>
/// <returns>
/// An instance of <see cref="IUpdateInfoModel" />.
/// </returns>
public IUpdateInfoModel Update(IParameterContainer parameterContainer)
{
Validate.ArgumentNotNull(parameterContainer, "parameterContainer");
string token;
parameterContainer.TryGet(TokenParameterName, out token, null);
if (string.IsNullOrEmpty(token))
{
throw new KeyNotFoundException("The key is to generate not found.");
}
ICaptchaValue captchaValue = StorageProvider.GetValue(token, TokenType.Validation);
if (captchaValue == null)
{
throw new ArgumentException("The key is to update incorrect.");
}
HttpRequestBase request;
if (!parameterContainer.TryGet(RequestParameterContainer.HttpRequestParameterKey, out request) ||
request == null)
{
throw new InvalidOperationException(
"The parameterContainer does not contain a HttpRequestBase with key RequestParameterContainer.HttpRequestParameterKey.");
}
KeyValuePair <string, ICaptchaValue> captchaPair = CreateCaptchaPair(parameterContainer, captchaValue);
string newUrl = ImageUrlFactory(new UrlHelper(request.RequestContext), captchaPair);
StorageProvider.Add(captchaPair);
return(new DefaultUpdateInfoModel(TokenElementName, captchaPair.Key, newUrl, ImageElementName));
}
/// <summary>
/// Creates a new <see cref="IDrawingModel" /> for drawing a captcha.
/// </summary>
/// <param name="parameterContainer">
/// The specified <see cref="IParameterContainer" />.
/// </param>
/// <returns>
/// An instance of <see cref="IDrawingModel" />.
/// </returns>
public virtual IDrawingModel GetDrawingModel(IParameterContainer parameterContainer)
{
Validate.ArgumentNotNull(parameterContainer, "parameterContainer");
string token;
if (!parameterContainer.TryGet(TokenParameterName, out token) || string.IsNullOrEmpty(token))
{
throw new KeyNotFoundException("The key is to generate not found.");
}
ICaptchaValue captchaValue = StorageProvider.GetValue(token, TokenType.Drawing);
if (captchaValue == null)
{
throw new ArgumentException("The key is to generate incorrect.");
}
return(DrawingModelFactory(parameterContainer, captchaValue));
}
/// <summary>
/// Serializes the <see cref="ICaptchaValue" />, to the given string.
/// </summary>
/// <param name="captchaValue">
/// The specified <see cref="ICaptchaValue" />.
/// </param>
/// <returns>The result string.</returns>
protected virtual string Serialize(ICaptchaValue captchaValue)
{
Validate.ArgumentNotNull(captchaValue, "captchaValue");
using (var pdb = new Rfc2898DeriveBytes(Password, Salt))
{
string value = captchaValue.GetType().FullName + Separator + captchaValue.Serialize();
byte[] bytes = Encoding.Unicode.GetBytes(value);
using (var ms = new MemoryStream())
{
Rijndael alg = Rijndael.Create();
alg.Key = pdb.GetBytes(32);
alg.IV = pdb.GetBytes(16);
using (var cs = new CryptoStream(ms, alg.CreateEncryptor(), CryptoStreamMode.Write))
{
cs.Write(bytes, 0, bytes.Length);
}
return(Convert.ToBase64String(ms.ToArray()));
}
}
}
/// <summary>
/// Generates a specified <see cref="KeyValuePair{TKey,TValue}" /> for a captcha.
/// </summary>
/// <param name="parameterContainer">
/// The specified <see cref="IParameterContainer" />.
/// </param>
/// <param name="oldValue">The old value if any.</param>
/// <returns>
/// An instance of <see cref="KeyValuePair{TKey,TValue}" />.
/// </returns>
protected virtual KeyValuePair <string, ICaptchaValue> CreateCaptchaPair(IParameterContainer parameterContainer,
ICaptchaValue oldValue)
{
if (parameterContainer.IsContains(MathCaptchaAttribute))
{
return(MathCaptchaPairFactory());
}
int length;
if (oldValue != null)
{
length = oldValue.CaptchaText.Length;
}
else if (!parameterContainer.TryGet(LengthAttribute, out length))
{
throw new ArgumentException("Parameter is not specified for the length of the captcha.");
}
if (length <= 0)
{
throw new ArgumentException("The length parameter can not be <= 0.");
}
return(PlainCaptchaPairFactory(length));
}
/// <summary>
/// Creates a new <see cref="IDrawingModel" /> for drawing a captcha.
/// </summary>
/// <param name="parameterContainer">
/// The specified <see cref="IParameterContainer" />.
/// </param>
/// <param name="captchaValue">
/// The specified <see cref="ICaptchaValue" />.
/// </param>
/// <returns>
/// An instance of <see cref="IDrawingModel" />.
/// </returns>
private static IDrawingModel CreateDrawingModel(IParameterContainer parameterContainer,
ICaptchaValue captchaValue)
{
return(new DefaultDrawingModel(captchaValue.CaptchaText));
}
